KR101647391B1 - A pigment particle composition, its method of manufacture and its use - Google Patents

Abstract

A pigment particle composition comprising calcium carbonate particles and pigment particles, a process for their preparation and their use are described. According to the present invention, calcium carbonate particles are carbonated such that they are bonded together to form a calcium carbonate structure, said calcium carbonate structure comprising pigment particles and forming an essentially opaque and stable pigment-calcium carbonate aggregate. The composition may be prepared by spraying a calcium hydroxide-containing pigment slurry with a carbon dioxide-containing gas, in which case the calcium hydroxide is carbonated to precipitate the calcium hydroxide particles to be adhered to each other and the carbonation is essentially all of the calcium hydroxide is converted to calcium carbonate Until then. The compositions are particularly suitable for use in paints, coating materials, fillers, polymers and printing inks.

Description

TECHNICAL FIELD [0001] The present invention relates to a pigment particle composition, a method for producing the pigment particle composition,

The present invention relates to a pigment particle composition according to the preamble of claim 1.

Such compositions generally comprise calcium carbonate particles and pigment particles.

The present invention also relates to a process for preparing a pigment particle composition according to the preamble of claim 22, and also to a paint, coating material, filler material, polymer and printing ink composition according to the preamble of claims 40-44.

Due to its high refractive index, titanium dioxide has been used as a light-scattering white pigment in paints, printing inks and many other coating compositions, and also in filler materials.

Titanium dioxide is expensive and difficult to reuse. In order to reduce the required amount, the titanium dioxide is typically mixed with the extender, but the amount of the extender must be kept very low, otherwise the optical properties obtained using titanium dioxide, especially the paint and coating compositions, Significant opacity is lost.

The object of the present invention is to eliminate the disadvantages associated with the known art and to produce a completely new pigment composition which can reduce the amount of light-scattering pigment without reducing the obtained optical properties, in particular the opacity.

The present invention is based on the idea that a shell comprising precipitated calcium carbonate is formed around the pigment particles and the envelope encapsulates at least partially one or several pigment particles.

According to the invention, in this case, the calcium carbonate particles are at least predominantly carbonated such that these particles are bonded together to form a calcium carbonate structure.

Such a structure includes one or several particles, but generally only one or two pigment particles together with calcium carbonate form an essentially opaque and stable pigment-calcium carbonate aggregate.

The composition may, for example,

- spraying a calcium hydroxide-containing aqueous slurry containing pigment particles with a carbon dioxide-containing gas to carbonate the calcium hydroxide;

- selecting the amount of calcium hydroxide in the aqueous slurry so that the percentage of calcium carbonate in the pigment composition is equal to a predetermined weight percent;

Carbonating the calcium hydroxide to carbonate the calcium carbonate particles to adhere to each other; And

- essentially by continuing carbonation until all of the calcium hydroxide has been converted to calcium carbonate.

The composition according to the present invention comprises a paint; Coating material compositions in paper or paperboard; A filler material composition in paper or paperboard; plastic; Or as a pigment in a printing ink.

More specifically, the composition according to the present invention is characterized primarily by those described in the characterizing part of claim 1.

The method according to the invention is in turn characterized by what is described in the characterizing part of claim 22, wherein the paint, the coating material, the filler material, the polymer and the printing ink composition according to the invention, .

Use according to the invention is characterized by what is described in claim 47.

Significant advantages can be obtained when using the present invention. Thus, excellent opacity is obtained with this pigment composition, and the pigment composition can be used in place of, for example, more than 50% by weight of titanium dioxide which is a white pigment in the paint composition.

We have found that in applications where the pigment particles are titanium dioxide, some or all of the titanium dioxide is replaced by calcium carbonate, a calcium carbonate change is already applied in a weight ratio of 10: 90-30: 70 between titanium dioxide and calcium carbonate Which is at least nearly as good as that of using 100% titanium dioxide.

The excellent properties of the composition according to the invention are mainly due to the fact that the pigment particles are separated from each other by a calcium carbonate structure such that the distance between these particles is at least about 60 nm, preferably at least about 100 nm, most preferably at least about 120 nm .

Since the price of calcium carbonate is substantially less than the price of titanium dioxide or the price of many other light-scattering pigment particles, the present invention provides a significant reduction in pigment cost.

It is important to note that, in particular for titanium dioxide, there is no substantial substitute for this (i.e., titanium dioxide) in the white cover pigments market. However, the disadvantage of using titanium dioxide is that it tends to aggregate, and in this case the light-scattering power of the titanium dioxide is greatly reduced. Another advantage of the present invention is that the present inventors have now found a way to efficiently utilize the high refractive index (light-scattering index) of titanium. In preparing the envelope according to the present invention, very cost effective materials can be used to replace expensive titanium dioxide, namely calcium oxide / calcium hydroxide and carbon dioxide.

Another problem associated with titanium dioxide in the case of application to paper and paperboard is that its retention quality is often poor because the product according to the invention has a larger particle size and lower density than titanium dioxide It is improved by using the product. Larger and lighter particles are more easily retained within the fiber network, and they are not removed with water (mechanical retention).

The process is simple and industrially useful: it is a very rapid and highly efficient carbonation process. Formation of the carbonate shell takes place in situ, in which case no separate preparation of PCC is required. The method can be applied on an industrial scale. According to one preferred embodiment of the present invention, the preparation of the pigment composition is carried out continuously.

In the following, the present invention will be described in more detail with reference to the detailed description and the accompanying drawings. In the drawings,
Figures 1a and 1b are electron micrographs of calcium carbonate-pigment particle compositions prepared according to the present invention;
2 schematically shows, by way of example, a vertical section of one of the precipitation reactors according to the invention;
Figure 3 schematically shows a horizontal cross-section of an injector fitted into the precipitation reactor according to Figure 2 as an example;
4 schematically shows a vertical cross-sectional view of a second precipitation reactor according to the present invention, for example;
Figure 5 schematically shows an example of the sprayer of the precipitation reactor according to Figure 4;
FIG. 6 schematically shows a vertical section of the precipitation reactor group according to the present invention as an example.

Figures 1a and 1b show electron micrographs of a calcium carbonate-pigment product comprising titanium dioxide particles prepared according to the present invention and wrapped in calcium carbonate particles. Calcium carbonate includes particles (i.e., precipitated calcium carbonate, PCC) produced from calcium hydroxide by a carbonation process. Figures 1a and 1b illustrate, in accordance with one embodiment of the present invention, a method of carbonizing typically calcium carbonate particles to attach them to one another in such a way that they form an envelope at least partially enclosing the at least one pigment particle do. Based on the analysis device, the thickness of the shell is at least about 30 nm, in particular at least about 50 nm, most preferably about 60 to 500 nm.

Based on the above photograph, the calcium carbonate particles are mainly non-spherical. Typically, their external form is at least predominantly rhombic or rhombohedric.

The particles are crystalline and their crystalline form is predominantly calcite or-less-aragonite.

Figures 1a and 1b show that the calcium carbonate particles form a polynuclear calcium carbonate structure to which the pigment particles adhere. From the test of the present inventors, it has been found that calcium carbonate particles and pigment particles, which are titanium dioxide particles, strongly adhere to each other in this photograph. Most (i. E., More than 50%, typically even 90 or more than 95%) of the calcium carbonate particles remain attached to the dry pigment composition and the calcium carbonate crystals in both of the aqueous slurries of the pigment composition.

The property "stable" used for calcium carbonate-pigment aggregates means that the calcium carbonate-pigment aggregates are dispersed in water and then dried or - on the contrary - they are dried in powder form and then dispersed in water, (At least about 50% by weight, especially about 75% by weight, most preferably at least about 90% by weight) of the pigment particles as a part remain attached to the calcium carbonate particles.

Opacity means that the calcium carbonate-pigment aggregate provides good opacity to the intermediate material as a pigment, where the aggregate is mixed into the intermediate material when replacing some or all of the pigment. Typically, this opacity has the same size as the pigment concerned (having a strain range of about 10%). Good opacity is believed to be due to the fact that pigment particles, which are primarily encased in an envelope, can be maintained at a distance from each other producing optimal opacity and that the particles are well retained and that these particles are uniformly distributed in the intermediate material .

The envelope formed of calcium carbonate particles wraps about 1 to 20, in particular about 1 to 10, preferably 1 to 3, pigment particles, partly or wholly. In the figure, it is difficult to distinguish between titanium dioxide individual particles and calcium carbonate because the former is completely wrapped by the latter. The calcium carbonate structure is formed of calcium carbonate particles, which have an inherent size of about 20 to 250 nm on average before carbonating them to carbonace the other particles. Once the calcium carbonate particles are coalesced, these particles form an essentially continuous surface.

The weight ratio between the pigment particles and the calcium carbonate particles is about 90: 10-5: 95, preferably about 60: 40-5: 95, and especially about 40: 60-10: 90. The composition according to Figs. 1a and 1b shows the case where the amount of titanium dioxide is on the average about 18% by weight and the amount of calcium carbonate is on the average about 82% by weight, based on the total amount of pigment and calcium carbonate.

In the preparation, the weight ratio between the light-scattering pigment and calcium carbonate is adjusted to the desired ratio by selecting the amount of calcium hydroxide and calcium carbonate in the carbonated slurry to be carbonated in such a way that the percentage of calcium carbonate in the final pigment composition corresponds to a predetermined weight percentage do.

The pigment composition may also comprise other components besides pigment particles and calcium carbonate particles, such as dispersants, surface modifiers and stabilizers or mixtures thereof. However, the total amount thereof is at most about 20% by weight, typically less than 10% by weight of the total weight of the composition.

Compositions according to the present invention are typically < RTI ID = 0.0 >

- carbonating the calcium hydroxide to produce calcium carbonate and, in turn, to produce a pigment composition, by spraying a calcium hydroxide-containing aqueous slurry comprising the pigment particles with a carbon dioxide-containing gas; And

By selecting the amount of calcium hydroxide in the aqueous slurry in such a way that the percentage of calcium carbonate in the pigment composition corresponds to the predetermined weight percent.

In this process, the calcium carbonate particles are precipitated from calcium hydroxide and carbon dioxide in such a way that the calcium carbonate particles are bonded to the surface of the pigment particles and they are carbonated to adhere to other calcium carbonate particles, and in this case an essentially opaque and stable pigment- Calcium aggregates are formed, which are at least partially covered with calcium carbonate particles.

Preferably, the calcium hydroxide-containing aqueous slurry comprising titanium dioxide particles is at least essentially free of fibers, in which case all of the precipitated calcium hydroxide can be used for coating the pigment particles.

The method can be adjusted to a desired ratio by selecting the weight ratio between pigment particles and calcium carbonate such that the amount of calcium hydroxide and the amount of calcium carbonate in the aqueous slurry correspond to a predetermined percentage by weight of calcium carbonate in the final pigment composition.

Typically, a calcium hydroxide-containing aqueous slurry containing pigment particles is guided through a high energy mixing zone in which the aqueous slurry is broken down into droplets or even into opaque droplets and then into a carbon dioxide containing gas Lt; / RTI > The carbonation continues until essentially all of the calcium hydroxide has been converted to calcium carbonate.

Figures 1a and 1b show a calcium carbonate composition comprising titanium dioxide. The crystalline form of titanium dioxide may in turn be rutile or anatase. However, the solution according to the invention is also suitable for other light-scattering and / or absorbing pigments such as aluminum hydroxide, barium sulfate, kaolin, gypsum, crushed or precipitated calcium carbonate, chalk or mixtures thereof, , Such as plastic pigments and furnace black, and mixtures thereof.

In the process according to the invention, the calcium hydroxide-containing aqueous slurry comprising pigment particles is dripped into the carbon dioxide-containing gas so as to carbonate the calcium hydroxide to form a pigment composition comprising calcium carbonate. The process is preferably carried out in an excess of carbon dioxide, in which case the formation of calcium carbonate is limited only by the amount of calcium hydroxide supplied into the system. In this state, the carbonation typically continues until the pH value of the pigment slurry becomes essentially neutral. There is no need to add any acid.

Processing with the processing apparatus will be described in detail below with reference to FIGS. 2 to 6. FIG. In general, it can be seen that it is advantageous to carry out carbonation in several stages. In this case, the aqueous slurry produced by spraying carbon dioxide-containing aqueous slurry with carbon dioxide gas along with carbonation is recovered, and this aqueous slurry is most suitably introduced for further carbonation.

According to one embodiment, the aqueous slurry is further carbonated by spraying it with carbon dioxide gas one or more times. In another embodiment, it is further carbonated by bubbling carbon dioxide gas into the slurry.

Typically, carbonation is carried out continuously in such a way that at least one spray is applied to the aqueous slurry. The light-scattering and aqueous calcium hydroxide containing slurry containing the pigment particles is then guided through a high energy mixing zone in which the aqueous slurry is decomposed into droplets or even opaque droplets and then dropped into a carbon dioxide containing gas . If desired, dispersants, surface modifiers or stabilizers or mixtures thereof are added to the pigment composition to be prepared during or after the preparation.

In particular, all of the aqueous calcium hydroxide-containing slurry can be added to the carbonation process together with the pigment particles. However, the aqueous calcium hydroxide-containing slurry may be introduced gradually and in batches into the carbonation process, wherein at least a portion of the aqueous calcium hydroxide-containing slurry most suitably contains a pigment when it is fed into the carbonation process Do not.

According to one embodiment, the pigment is possibly added little by little, apart from the calcium hydroxide.

The process is typically carried out at a temperature of from about 30 to 100 占 폚, especially from about 50 to 80 占 폚.

Hereinafter, the application examples shown in the drawings will be described in more detail.

Figure 2 is a continuously operating precipitation reactor 10 in accordance with the present invention in which the reactor comprises a settling vessel 12, an injector 14 fitted to a settling vessel, a calcium hydroxide-containing aqueous slurry containing titanium dioxide particles A supply tube 16, an inlet tube 18 for the settling gas, and a discharge tube 20 for the treated pigment composition. The apparatus also includes an actuator 22 that includes a bearing and a sealing assembly 24 positioned between an actuator 22 and a sprayer 14. The actuator 22 includes an actuator 22,

The sprayer 14 (whose horizontal section is shown in Fig. 3) includes six coaxial rings 26, 26'a, 26'a, 28a, 28'a, 28''a with blades 26a, Flow mixer having a plurality of nozzles 26 ', 26 ", 28, 28', 28". In this apparatus 14, a calcium hydroxide-containing aqueous slurry containing titanium dioxide particles is dropped to form small particles, liquid droplets, and / or solid particles. The dwell time in the sprayer is less than 10 seconds, typically less than 2 seconds, most typically less than 1 second.

As indicated by the arrows in Figure 3, a set of rings 26, 26 ', 26 "of the atomizer functions as a rotor that rotates counterclockwise in the case of Figure 3. The first set Another set of rings 28, 28 ', 28 "alternately located between the rings also serves as a rotor; However, they rotate clockwise in this case. The blades 26a, 26a ', 26a " and 28, 28a', 28a "mounted on two sets of rings encounter a pigment composition moving outwardly and radially through the device, And double shocks. Containing aqueous slurry containing pigment particles, using an apparatus having a fixed ring, i.e., a stator, between rings rotating in each set of clockwise directions and also between rings rotating in each set of counterclockwise directions Can be dropped.

A calcium hydroxide-containing aqueous slurry containing titanium dioxide particles is fed via line 16 to the center 30 of the atomizer from which the slurry is drawn to form a mixture of the movement of the rotor blades and the pressure difference Resulting in radially outward movement toward the open outer edge 32 of the outer ring 28. This aqueous slurry can also be fed into the device 14 between the rings if desired. Titanium particles and calcium hydroxide-containing aqueous slurry can be fed to the sprayer 14 via separate tubes, in which case a calcium hydroxide-containing aqueous slurry comprising titanium dioxide particles is not formed prior to this point.

The turbulence and pulse of low pressure and excess pressure caused by shock and double impact, shear force, motion of the rotor blade rotating in the opposite direction, and calcium hydroxide containing aqueous slurry containing titanium dioxide particles, , Liquid droplets and solid particles. By using a rotor that rotates in the same direction but rotates at very different speeds, or by using a rotor-stator combination, the same effect can be produced.

In the solution according to the invention shown in Figures 2 and 3, the settling gas is guided through the tube 18 to the center 30 of the atomizer ring. From this center, gas flows radially outwards, creating a gaseous space 34 containing the settling gas, in and around the spray vessel 12, in the atomizer. The gas is discharged through a tube 21 located at the top of the precipitation reactor. If desired, the settling gas can be supplied to the ring and / or between the rings of the atomizer. The precipitation reaction may already be initiated in the gaseous space of the atomizer.

When treated in the sprayer 14, a calcium hydroxide-containing aqueous slurry comprising titanium dioxide particles produces micro droplets and particles, which droplets and particles flow from the device 14 into the surrounding portion 34 'of the gaseous space Lt; / RTI > The droplets and particles are forced out of the sprayer, primarily from the outer ring region of the sprayer, to the opaque flow 36. After being discharged from the atomizer, the precipitation reaction can continue for a relatively long time while the micro droplets and particles are dispersed widely in the precipitation vessel. The treated fiber composition descends to a pool at the bottom of the precipitation vessel and is discharged from the vessel via a tube (20).

The appropriate size, shape, width and height of the settling vessel 12 can be selected so that the droplets and particles discharged from the atomiser remain in the gaseous space 34 'of the settling vessel for an optimal residence time. For example, increasing the height of the sedimentation vessel 12 to be in a tower configuration increases the retention time of the fiber composition.

The process in the precipitation reactor 10 can also be adjusted, for example, by adjusting the number of rings, the distance between the rings, the distance between the blades on each ring, and the blade dimensions and position, within the atomizer.

The pigment composition discharged through the bottom of the settling vessel 12 may be recycled back to the same precipitation reactor or fed to another reactor to complete the treatment.

Figures 4 and 5, which illustrate other precipitation reactors according to the present invention together with an atomizer, use the same reference numerals as shown in Figures 1 and 2, where applicable. According to the present invention, the other precipitation reactor 10 shown in Fig. 4 mainly comprises a sprayer 14 having an outer ring with the reactor closed, and in that the precipitation reactor comprises a separate precipitation zone extending beyond the sprayer But differs from the apparatus shown in Figures 2 and 3 in that it does not. The solution shown in Figures 4 and 5 is suitable for use when, for example, the precipitation reaction is already considered to be completed in the desired manner in the gaseous space of the atomizer.

In the sprayer shown in FIGS. 4 and 5, the outermost ring 28 'is surrounded by a housing 40 that seals the ring. The housing includes a discharge opening (42) for discharging the treated fiber composition from the device (14). The treated fiber composition can be guided from the discharge opening 42 through a tube for further processing or further processing. As shown in Figure 4, the material discharged from the precipitation reactor can also be recycled back to the same reactor or guided to another reactor to complete the carbonation.

Two or more of the two types of precipitation reactors shown in Figures 2 and 4 may be arranged in a sequential series. Figure 6 shows three settling reactor groups arranged in series. The first reactor is of the type shown in Fig. 4 and the following two reactors are of the type shown in Fig. Where applicable, the reference numerals are the same as in the previous drawings.

6 is a three precipitation reactors (10, 10 ', 10 ") a illustrates, in this case the calcium hydroxide-containing aqueous slurry containing titanium dioxide particles are to carbonation a Ca ^{2 +} ion, that is CO ₂ in order to precipitate the CaCO ₃ Containing aqueous slurry containing titanium dioxide particles is guided from the top through a tube to the first precipitation reactor 10 in which the carbon dioxide containing gas is also guided through the tube 18. The partially carbonated pigment composition is guided to the second precipitation reactor 10 'via a break tank 48. After the first precipitation reactor, the calcium hydroxide to be precipitated is introduced into the aqueous slurry to be treated, 52). ≪ / RTI >

From the brake tank 48, the partially treated aqueous slurry containing the pigment composition and the unfiltered calcium hydroxide is guided to the feed pipe 16 of the second reactor 10 'through the exhaust duct, And is guided to the sprayer 14 of the precipitation reactor. Precipitation gas 18 ', typically carbon dioxide, is directed to the apparatus 14 with the pigment composition. Correspondingly, the aqueous slurry containing the pigment composition treated in the second reactor 10 'and the non-precipitated calcium hydroxide is guided to the feed pipe 16' of the third reactor 10 '' through the exhaust pipe 20 '. From the bottom of the third reactor 10 ", primarily the previously treated pigment composition, in which the weight ratio between titanium dioxide and calcium carbonate is predetermined, is removed via tube 20 ".

Calcium hydroxide or calcium carbonate may be added at any stage of the process prior to completion of the pigment composition in the final reactor. The average size of the combined calcium carbonate particles can be influenced by the addition of calcium hydroxide. To achieve the desired weight ratio between titanium dioxide and calcium carbonate, titanium dioxide may also be added at any stage of the process before the pigment composition is completed in the final reactor.

The carbon dioxide-containing gas is guided to the respective reactors through tubes 18, 18 ', 18 ". The carbon dioxide-containing gas is supplied to the first reactor 10 via a supply line 18, The carbonaceous particles produced are precipitated on the titanium dioxide particles and to some extent the calcium carbonate particles are also deposited on top of one another. To complete the precipitation reaction (carbonation), the same or another carbon dioxide- 18 ", 18 ") to the second and third settling reactors 10 ', 10 ". The gas is removed from the reactor via the outlet tubes 21, 21', 21 ". Typically the gas to be removed includes steam and carbon dioxide. The gas is guided for treatment in the gas scrubbing and cooling device 54. In the apparatus 54, the treated carbon dioxide-containing gas is recycled back to the precipitation reactor.

The compositions prepared are suitable for a number of applications in which conventional pigments such as titanium dioxide are currently in use. Some examples are given below:

Paint compositions, including pigments and binders, and conventional manufacturing materials and additives used in paints,

Coating materials compositions comprising pigments and binders, and customary manufacturing materials and additives used in coating materials,

A filler composition comprising a pigment, and conventional manufacturing materials and additives used in the filler composition,

A polymer composition comprising a thermoplastic polymer in which a pigment and, possibly, conventional manufacturing materials and additives used in the polymer composition are mixed.

A printing ink composition comprising a liquid phase mixed pigment, a binder and possibly a color pigment, and other manufacturing materials and additives used in the printing ink composition.

In all of these pigments, at least 1 wt.%, Most preferably at least 5 wt.%, Especially at least about 20 wt.% Of the pigment comprises calcium carbonate-pigment agglomerates according to any of the above applications.

The invention is illustrated by the following non-limiting examples.

Example  One

Preparation of pigment particle composition

The raw materials used in the test

1. Ca (OH) ₂ aqueous slurry with a dry matter content of approximately 17%, T = 60 ° C.

2. Commercial elutriated titanium dioxide, washed with about 50% dry matter, T = 20 ℃.

3. CO ₂ -containing gas, T = 20 ° C.

In the process according to the invention, the required amount of Ca (OH) ₂ slurry and titanium dioxide slurry is fed into the settling reactor group shown in Figure 6 so that the titanium dioxide / PCC mass ratio after precipitation is 30/70, . Excess carbon dioxide-containing gas was also fed to the precipitation reactor. A titanium calcium hydroxide-containing aqueous slurry containing titanium dioxide particles was broken down into small droplets in a carbon dioxide-containing gas by guiding the slurry through a high energy mixing zone.

The partially treated pigment composition was pumped from a first precipitation reactor into a second precipitation reactor and was also pumped from the second precipitation reactor to a third precipitation reactor from which the dry matter content was 24% A pigment particle composition according to the present invention was obtained. After the third precipitation reactor, the pH of the pigment composition was 6.9 and essentially all of Ca (OH) ₂ precipitated as calcium carbonate. The percentage of calcium carbonate in the pigment composition was determined by titration. The result was 69.9% as desired.

Example  2

In the method according to the present invention, a pigment composition having a mass ratio of titanium dioxide to calcium carbonate of 18/82 was prepared. The dry matter content of this composition was increased to 60% and a dispersant was added thereto to obtain a very fluid pigment slurry. Using this product, a sufficiently matte and heavily loaded (PVC > 70%) primer was obtained that prevented any other ingredients from being modified, except that 50 parts by weight of titanium dioxide was replaced by a pigment composition according to the invention in an equivalent amount (Calculated as dry to dry weight).

Titanium dioxide constituted 8.0 wt% of the reference paint.

The test point included 4.0% by weight of titanium dioxide and 4.0% by weight of the pigment composition according to the invention. The coverage of the paint prepared in this way was measured and the following results were obtained.

Reference Example 96.3%

Test point 96.2%

Example  3

Water was removed from the pigment composition according to Example 1 using a centrifuge and a dispersant was added to obtain a highly fluid pigment slurry with a dry matter content of 60%. This product was used as a replacement for the titanium dioxide used to coat the cardboard in such a way that no other components of the coating paste were affected. The reference paste consisted of 4 parts by weight of titanium dioxide and 96 parts by weight of ground calcium carbonate. At the test point 1, half of the titanium dioxide and at the test point 2 all of the titanium dioxide was replaced by the pigment composition according to the invention. This paste was applied on a plate at a rate of 12 g / m 2. The coating layer was removed from the final paperboard by dissolution and then the opacity of the paperboard was measured. The following results were obtained:

Reference Example 78.4%

Test point 1 78.3%

Test point 2 78.6%

Example  4

The titanium dioxide used as a filler in paper was replaced with the pigment composition according to the invention in such a way that no other ingredients used in the paper production were altered. As a second reference example, a number of papers were prepared using a mixture of titanium dioxide and scalenohedric commercial PCC as fillers, the ratio of which in the product according to the invention was between titanium dioxide and carbonic acid Potassium ratio, i.e., 30/70. The weight of the paper was 60 g / m 2 and the filler percentage was 10%. The opacity of the paper sheet produced in this way was measured and the following results were obtained:

Reference Example 1 85.5%

Reference Example 2 83.8%

Test point 1 85.7%

The present invention is not limited to the above description and examples. Instead, the present invention is extensively applied within the limits set forth in the claims set forth below.

Claims (60)

As pigment particle compositions comprising calcium carbonate particles and pigment particles,
Wherein the calcium carbonate particles are non-spherical and some or all of the calcium carbonate particles are carbonated so that the calcium carbonate particles bond together to form a calcium carbonate structure that encapsulates one or more pigment particles and the calcium carbonate particles form calcite or aragonite wherein the outer shape of the calcium carbonate particles is rhombic or rhombohedric,
Wherein the calcium carbonate particles form a shell that partially or wholly encapsulates the one or more pigment particles and form together with the pigment particles a pigment-calcium carbonate aggregate comprising two or more pigment particles and having the same opacity as the pigment In addition,
Wherein the weight ratio of the pigment particles to the calcium carbonate particles is 90: 10-5: 95 and when the pigment particle composition is dispersed in water and dried, more than 50% by weight of the pigment particles remain attached to the calcium carbonate particles, Composition. delete delete The pigment particle composition according to claim 1, wherein the calcium carbonate particles form a polynuclear calcium carbonate structure and pigment particles adhere to the polynuclear calcium carbonate structure. delete delete 2. A process according to claim 1 wherein the calcium carbonate crystals are present in an amount of greater than 95% by weight of the pigment in such a manner that in both the dry pigment composition and the aqueous slurry of the pigment composition the calcium carbonate crystals remain attached to more than 95% ≪ / RTI > is attached to the particle. The pigment particle composition according to claim 1, characterized in that the envelope formed of calcium carbonate particles partially or wholly covers 2 to 20 pigment particles. The pigment particle composition according to claim 1, wherein the calcium carbonate structure is formed of calcium carbonate particles and the average size of the calcium carbonate particles is 20 to 250 nm. The pigment particle composition of claim 1, wherein the pigment composition comprises a component selected from the group consisting of a dispersant, a surface modifier, a stabilizer, and mixtures thereof. delete The method according to claim 1,
- carbonating the calcium hydroxide to produce calcium carbonate and, in turn, to produce a pigment composition, spraying the calcium hydroxide-containing aqueous slurry comprising the pigment particles with a carbon dioxide-containing gas;
By selecting the amount of calcium hydroxide in the aqueous slurry so that the percentage of calcium carbonate in the pigment composition is between 10 and 95% by weight. The method according to claim 1, wherein the weight ratio between the pigment particles and the calcium carbonate is selected such that the amount of calcium hydroxide and the amount of calcium carbonate in the aqueous slurry are in the range of 10 to 95% by weight of the calcium carbonate in the final pigment composition, Lt; RTI ID = 0.0 > 1, < / RTI > 13. The method of claim 12, wherein the calcium hydroxide-containing aqueous slurry comprising pigment particles is guided through an impact mixer, the aqueous slurry in the impact mixer is broken down into droplets or even into opaque droplets, ≪ / RTI > by weight. 13. The pigment particle composition of claim 12, wherein the carbonation reaction continues until all of the calcium hydroxide has been converted to calcium carbonate. 15. The pigment particle composition according to claim 14, wherein the aqueous calcium hydroxide-containing aqueous slurry of pigment particles is free of fibers. The method of claim 1 wherein the pigment is a light-scattering pigment, an absorbing pigment, a light-scattering and absorbing pigment, or an organic pigment material,
The light-scattering pigment, the absorbing pigment, or the light-scattering and absorbing pigment is selected from the group consisting of titanium dioxide, aluminum hydroxide, barium sulphate, kaolin, gypsum, ground or precipitated calcium carbonate,
Wherein the organic pigment material is selected from the group consisting of plastic pigments, furnace black, and mixtures thereof. The pigment particle composition according to claim 1, wherein the pigment particles are titanium dioxide. The pigment particle composition according to claim 1, characterized in that the crystal form of titanium dioxide used as the pigment particles is rutile or anatase. The pigment particle composition according to claim 1, wherein the pigment particles are separated from each other by a calcium carbonate structure in such a way that the distance between the pigment particles is at least 60 nm on average. The pigment particle composition according to claim 1, characterized in that the thickness of the envelope formed by the calcium carbonate structure is on average 30 nm or more. A process for the preparation of the pigment particle composition according to claim 1, wherein the pigment particles are combined with the calcium carbonate particles,
- to carbon dioxide the calcium hydroxide and, in turn, to produce a pigment composition comprising calcium carbonate, spraying the calcium hydroxide-containing aqueous slurry containing the pigment particles with a carbon dioxide-containing gas,
The amount of calcium hydroxide in the aqueous slurry is selected such that the percentage of calcium carbonate in the pigment composition is from 10 to 95% by weight;
Carbonating the calcium hydroxide to precipitate the calcium carbonate particles to be adhered to each other and continuing carbonation until all of the calcium hydroxide is converted to calcium carbonate. 23. The process of claim 22, wherein the process is carried out in an excess of carbon dioxide. 23. The method of claim 22, wherein the carbonation continues until the pH value of the pigment slurry is neutral. 23. The method of claim 22, wherein the carbonation is carried out in several stages. 26. The method for producing a pigment particle composition according to claim 25, wherein an aqueous slurry obtained by spraying and carbonizing the aqueous calcium hydroxide-containing slurry with a carbon dioxide gas is recovered and introduced into a further carbonation furnace. 27. The method of claim 26, wherein the aqueous slurry is further carbonated by spraying it with carbon dioxide gas once more or by bubbling carbon dioxide gas into the slurry. 23. The method of claim 22, wherein the carbonation is carried out continuously such that the aqueous slurry is dripped once or more. 23. The method of claim 22, wherein all of the calcium hydroxide-containing aqueous slurry is added into the carbonation process together with the pigment particles. 23. The method of claim 22, wherein the aqueous calcium hydroxide-containing slurry is added stepwise into the carbonation process. 31. The method of claim 30, wherein some or all of the calcium hydroxide-containing aqueous slurry does not contain a pigment when it is fed into the carbonation process. 32. The method of claim 31, wherein the amount of calcium hydroxide and calcium carbonate in the aqueous slurry of the carbonation process is selected such that the percentage of calcium carbonate in the final pigment composition is from 10 to 95 percent by weight, By weight based on the total weight of the pigment particles. 23. The method according to claim 22, wherein the pigment is added little by little, possibly in addition to calcium carbonate. 23. The method of claim 22 wherein the aqueous slurry containing calcium hydroxide containing light-scattering pigment particles is guided through an impact mixer wherein the aqueous slurry is broken down into droplets or even into opaque droplets, Containing gas into a carbon dioxide-containing gas. 35. The method of claim 34, wherein the calcium hydroxide-containing aqueous slurry comprising pigment in the impact mixer is applied to a rotor-stator using a rotor blade rotating in the opposite direction or rotating in the same direction but at a different speed, Characterized in that it is added dropwise with a combination of fine particles, liquid droplets, solid particles, or a mixture thereof. 23. The method of claim 22, wherein a dispersant, a surface modifier, or a stabilizer, or a mixture thereof, is added into the aqueous slurry of calcium hydroxide. 23. The method of claim 22, wherein the calcium carbonate particles are precipitated in such a way that the calcium carbonate particles are bonded to the surface of the titanium dioxide particles and are carbonated such that they are bound to other calcium carbonate particles, in which case titanium dioxide- calcium carbonate aggregates are produced, Characterized in that the aggregates are at least partially covered with calcium carbonate particles. 23. The process according to claim 22, which is carried out at a temperature of from 30 to 100 占 폚. 23. The method of claim 22, wherein the aqueous calcium hydroxide-containing slurry of titanium pigment particles is free of fibers. A paint composition comprising pigments, binders, and additives used in paints,
Characterized in that at least 1% by weight of the pigment comprises the pigment particle composition according to claim 1. A coating material composition comprising pigments, binders, and additives used in coating materials,
Characterized in that at least 1% by weight of the pigment comprises the pigment particle composition according to claim 1. A filler composition comprising a pigment, and an additive for use in a filler composition,
Characterized in that at least 1% by weight of the pigment comprises the pigment particle composition according to claim 1. A polymer composition comprising a thermoplastic polymer mixed with a pigment, and an additive used in the polymer composition,
Characterized in that at least 1% by weight of the pigment comprises the pigment particle composition according to claim 1. A pigment mixed in a liquid phase; Binder; A printing ink composition comprising a color pigment and an additive used in a printing ink composition,
Characterized in that at least 1% by weight of the pigment comprises the pigment particle composition according to claim 1. Pigments; Binder; And a composition comprising a paint, a coating material, a filler composition, a polymer composition, or an additive used in a printing ink composition,
Wherein at least 5% by weight of the pigment comprises the pigment particle composition according to claim 17, wherein the light-scattering pigment in the composition is titanium dioxide. Pigments; Binder; And a composition comprising a paint, a coating material, a filler composition, a polymer composition, or an additive used in a printing ink composition,
Wherein at least 20% by weight of the pigment comprises the pigment particle composition according to claim 17, wherein the light-scattering pigment in the composition is titanium dioxide. 18. The system of claim 17, further comprising: a paint; Coating material compositions in paper or paperboard; Filler compositions in paper or paperboard; plastic; Or as a pigment in a printing ink. 50. The pigment particle composition of claim 47, wherein the light-scattering pigment is titanium dioxide. The pigment particle composition according to claim 8, characterized in that the envelope formed of calcium carbonate particles partially or wholly covers 2 to 10 pigment particles. The pigment particle composition according to claim 8, characterized in that the envelope formed of calcium carbonate particles partially or wholly covers 2 to 3 pigment particles. The pigment particle composition according to claim 1, wherein the weight ratio between the pigment particles and the calcium carbonate particles is 60:40 to 5:95. The pigment particle composition of claim 1, wherein the weight ratio between the pigment particles and the calcium carbonate particles is 40: 60-10: 90. delete delete 21. The pigment particle composition according to claim 20, wherein the pigment particles are separated from each other by a calcium carbonate structure in such a way that the distance between the pigment particles is at least 100 nm on average. The pigment particle composition according to claim 20, wherein the pigment particles are separated from each other by a calcium carbonate structure in such a way that the distance between the pigment particles is at least 120 nm on average. 22. The pigment particle composition according to claim 21, wherein the thickness of the shell formed by the calcium carbonate structure is 50 nm or more on average. 22. The pigment particle composition according to claim 21, wherein the thickness of the envelope formed by the calcium carbonate structure is on average from 60 to 500 nm. 25. The process according to claim 24, characterized in that carbonation is continued without adding any additional acid until the pH value of the pigment slurry is neutral. The process of claim 38, wherein the process is carried out at a temperature of from 50 to 80 캜.

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